Articulating surgical instruments

ABSTRACT

Articulating surgical instruments are disclosed. In one embodiment, a surgical instrument may include an elongated shaft assembly including an articulable portion moveable between a non-articulated configuration and an articulated configuration. First and second articulating shafts of the elongated shaft assembly may be coaxially arranged and axially fixed at an attachment point located distally from the articulable portion. Proximal portions of the first and second articulating shafts may be displaceable in opposing directions to articulate the articulable portion from the non-articulated configuration to the articulated configuration. In another embodiment, an articulation control may be movable from a first position to a second position to move an articulation lock from a locked configuration to an unlocked configuration to selectively permit articulation of a surgical instrument. The articulation lock also may be movable from the second position to a third position to articulate the surgical instrument.

FIELD

Disclosed embodiments are related to articulating surgical instruments.

BACKGROUND

A surgical mesh fabric or other prosthetic repair fabric may be used tosurgically repair a hernia. The prosthetic repair fabric is typicallyplaced in an open procedure or laparoscopically. Oftentimes a surgicalinstrument is used to secure the repair fabric in place by deploying oneor more fasteners from a distal end of the surgical instrument throughthe prosthetic repair fabric and into the underlying tissue. However, asurgical instrument that includes a rigid elongated shaft assembly fordeploying the fasteners may have a limited range of motion within thesurgical field. Consequently, many surgical instruments include at leastone articulable portion along the elongated shaft assembly to facilitatethe orientation and placement of fasteners within the surgical field.

SUMMARY

In one embodiment, a surgical instrument includes a handle and anelongated shaft assembly extending distally from the handle. Theelongated shaft assembly includes an articulable portion movable betweena non-articulated configuration and an articulated configuration. Theelongated shaft assembly includes a first articulating shaft and asecond articulating shaft coaxially arranged relative to the firstarticulating shaft and axially fixed relative to the first articulatingshaft at a location located distally from the articulable portion of theelongated shaft assembly. A proximal portion of the first articulatingshaft is displaceable in a distal direction and a proximal portion ofthe second articulating shaft is displaceable in a proximal direction tomove the articulable portion of the elongated shaft assembly from thenon-articulated configuration to the articulated configuration.

In another embodiment, a method of operating a surgical instrumentincludes displacing a proximal portion of a first articulating shaft ofan elongated shaft assembly of a surgical instrument in a proximaldirection. The elongated shaft assembly includes an articulable portionmovable between a non-articulated configuration and an articulatedconfiguration. The method also includes displacing a proximal portion ofa second articulating shaft of the elongated shaft assembly in a distaldirection. The second articulating shaft is coaxially arranged relativeto the first articulating shaft and axially fixed relative to the firstarticulating shaft at location located distally from an articulableportion of the elongated shaft assembly. The method further includesarticulating the elongated shaft assembly from the non-articulatedconfiguration to the articulated configuration, at least in part, due tothe displacement of the proximal portion of the first articulating shaftand the proximal portion of the second articulating shaft.

In a further embodiment, a surgical instrument includes a handle and anarticulation cam that is movable relative to the handle between at leasta first position and a second position. The articulation cam includes afirst cam profile and a second cam profile. The surgical instrumentfurther includes an elongated shaft assembly extending distally from thehandle, and the elongated shaft assembly includes a first shaftincluding a proximal portion coupled to the first cam profile and asecond shaft including a proximal portion coupled to the second camprofile, the second shaft coaxially arranged relative to the firstshaft. Moving the articulation cam from the first position to the secondposition displaces the proximal portion of the first shaft in a firstdirection and the proximal portion of the second shaft in a seconddirection.

In yet another embodiment, a method of operating a surgical instrumentincludes moving an articulation cam from a first position to a secondposition relative to a handle of a surgical instrument. The surgicalinstrument includes an elongated shaft assembly extending distally fromthe handle. The elongated shaft assembly includes a first shaft and asecond shaft coaxially arranged relative to the first shaft. Thearticulation cam includes a first cam profile coupled to a proximalportion of the first shaft and a second cam profile coupled to aproximal portion of the second shaft. The method further includesdisplacing the proximal portion of the first shaft in a first direction,at least in part, due to movement of the articulation cam from the firstposition to the second position, and displacing the proximal portion ofthe second shaft in a second direction opposite the first direction, atleast in part, due to movement of the articulation cam from the firstposition to the second position.

In another embodiment, a surgical instrument includes a handle and anelongated shaft assembly extending distally from the handle. Theelongated shaft assembly includes an articulable portion movable betweena non-articulated position and an articulated position. The surgicalinstrument further includes an articulation lock that selectivelyprevents articulation of the articulable portion of the elongated shaftassembly when the articulation lock is in a first locked configurationand permits articulation of the articulable portion of the elongatedshaft assembly when the articulation lock is in a second unlockedconfiguration. The surgical instrument also includes an articulationcontrol that controls articulation of the articulable portion of theelongated shaft assembly. Moving the articulation control from a firstposition to a second position moves the articulation lock from the firstlocked configuration to the second unlocked configuration to permitarticulation of the articulable portion of the elongated shaft assembly,and moving the articulation control from the second position to a thirdposition articulates the articulable portion of the elongated shaftassembly from the non-articulated position to the articulated position.

In a still further embodiment, a method of operating a surgicalinstrument includes moving an articulation control of a surgicalinstrument from a first position to a second position. The surgicalinstrument includes an elongated shaft assembly extending distally froma handle, and the elongated shaft assembly includes an articulableportion movable between a non-articulated position and an articulatedposition. The method further includes moving an articulation lock of thesurgical instrument from a first locked configuration to a secondunlocked configuration during movement of the articulation control fromthe first position to the second position. The articulation lockselectively prevents articulation of an articulable portion when thearticulation lock is in the first locked configuration, and thearticulation lock permits articulation of the articulable portion whenthe articulation lock is in the second unlocked configuration. Themethod also includes moving the articulation control from the secondposition to a third position, and articulating the articulable portionof the elongated shaft assembly from the non-articulated position to thearticulated position during movement of the articulation control fromthe second position to the third position.

In another embodiment, a surgical instrument includes a handle and anelongated shaft assembly extending distally from the handle. Theelongated shaft assembly includes an articulable portion movable betweena non-articulated configuration and an articulated configuration. Theelongated shaft assembly includes a first shaft including an articulableportion having a first plurality of cuts spaced along a first length ofat least a distal portion of the first shaft. Each cut of the firstplurality of cuts extends partially around a circumference of the firstshaft to define a first spine extending along the first length of thefirst shaft, and the first spine has a first width at a distal end ofthe first spine and a second width greater than the first width at aproximal end of the first spine. The elongated shaft assembly furtherincludes a second shaft coaxially arranged relative to the first shaft,and the second shaft includes an articulable portion having a secondplurality of cuts spaced along a second length of at least a distalportion of the second shaft. Each cut of the second plurality of cutsextends partially around a circumference of the second shaft to define asecond spine extending along the second length of the second shaft, andthe second spine has a third width at a distal end of the second spineand a fourth width greater than the third width at a proximal end of thefourth spine. The first spine is located on a first side of theelongated shaft assembly, and the second spine is located on a second,opposing side of the elongated shaft assembly.

It should be appreciated that the foregoing concepts, and additionalconcepts discussed below, may be arranged in any suitable combination,as the present disclosure is not limited in this respect. Further, otheradvantages and novel features of the present disclosure will becomeapparent from the following detailed description of various non-limitingembodiments when considered in conjunction with the accompanyingfigures.

In cases where the present specification and a document incorporated byreference include conflicting and/or inconsistent disclosure, thepresent specification shall control. If two or more documentsincorporated by reference include conflicting and/or inconsistentdisclosure with respect to each other, then the document having thelater effective date shall control.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures may be represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1 is a schematic representation of one embodiment of an articulablesurgical instrument;

FIG. 2 is a side view of an interior portion of the articulable surgicalinstrument of FIG. 1;

FIG. 3 is an exploded view of the elongated shaft assembly of thesurgical instrument of FIG. 1;

FIG. 4 is an exploded view of a portion of the elongated shaft assemblyof FIG. 3;

FIG. 5 is a side view of the first and second articulating shafts of thesurgical instrument of FIG. 1;

FIG. 6 is a close up side view of the surgical instrument of FIG. 1including an articulation control system according to one embodiment,with the articulation control system in a first position;

FIG. 7 is a side view of one embodiment of an articulation cam;

FIG. 8 is a perspective view of the articulation cam of FIG. 7;

FIG. 9 is a perspective view of one embodiment of a locking cam;

FIG. 10 is an exploded view of a portion of the articulation controlsystem of FIG. 6;

FIG. 11 is a perspective view of a portion of the articulation controlsystem of FIG. 6 in the first position;

FIG. 12 is a side view of the articulation control system of FIG. 6 in asecond position;

FIG. 13 is a side view of the articulation control system of FIG. 6 in athird position;

FIG. 14 is a perspective view of the portion of the articulation systemof FIG. 11, with the articulation control system in a third position;

FIG. 15 is a schematic plot depicting movement of components of anarticulation control system, according to one embodiment;

FIG. 16 is a side view of the locking shaft of the surgical instrumentof FIG. 1;

FIG. 17 is a side view of the first articulating shaft of the surgicalinstrument of FIG. 1;

FIG. 18 is a side view of the second articulating shaft of the surgicalinstrument of FIG. 1;

FIG. 19 is a perspective view of the driveshaft of the surgicalinstrument of FIG. 1;

FIG. 20 is a side view of the driveshaft of FIG. 19;

FIG. 21 is a rear perspective view of a portion of a surgicalinstrument;

FIG. 22 is a perspective view of one embodiment of a fastener levelindicator system; and

FIG. 23 is a perspective bottom view of the fastener level indicatorsystem of FIG. 22.

DETAILED DESCRIPTION

The inventors have appreciated numerous benefits associated withsurgical instruments that include an elongated shaft assembly having anarticulable portion to allow at least a portion of the surgicalinstrument to be placed in one or more desired configurations and/ororientations. For example, articulation of the articulable portion mayallow a distal tip of the elongated shaft assembly to be easily placedat desired position(s) and/or orientation(s) for performing a surgicalprocedure, such as deploying a surgical fastener into tissue. In someinstances, it may be desirable to selectively permit or preventarticulation of the elongated shaft assembly with an articulation lock.For example, it may be desirable to prevent articulation duringinsertion and extraction of the surgical instrument into a surgicalfield, as may occur during laparoscopic surgery, and/or when it isdesired to deploy fasteners in an unarticulated configuration. Thus, insome embodiments, the inventors have recognized that it may be desirableto provide a single integrated articulation control to allow a user toboth selectively lock and unlock the articulation lock and controlarticulation of the articulable portion. Such an integrated articulationcontrol may eliminate the use of a separate control for the articulationlock which may avoid adding additional steps and complexity to thetypical operation of such a surgical device.

In some embodiments, the inventors have also appreciated benefitsassociated with articulable surgical instruments in which axial movementof a distal tip of an articulable shaft assembly is minimized when anarticulable portion of the articulable shaft assembly is moved between anon-articulated configuration and an articulated configuration. Forinstance, maintaining an axial position of the distal tip duringarticulation may aid with accurate placement of the tip when deploying afastener or performing another suitable surgical procedure.

Additionally, in yet other embodiments, the inventors have recognizedthat it may be desirable to provide an articulable elongated shaftassembly with sufficient rigidity to avoid excessive deflection of theelongated shaft assembly during actuation of the device when theelongated shaft assembly is in an articulated configuration. Suchrigidity may help to maintain a distal tip of the elongated shaftassembly in a desired position and/or orientation during a surgicalprocedure and/or avoid excessive deflection of the shaft assembly when aforce is applied to the distal tip. For example, the distal tip may bepressed into contact with a surface when deploying a fastener intotissue, and the rigidity of the elongated shaft assembly may limit thedeflection of the tip to be less than a desired threshold deflection fora predetermined force applied to the distal tip.

As used herein, the term “distal direction” within a surgical device mayrefer to a direction that extends along a central longitudinal axis ofthe surgical device towards a distal end of the surgical device where adesired operation is performed. Correspondingly, a “proximal direction”may refer to a direction that is directed in an opposite directionrelative to the distal direction such that it may be directed along thecentral longitudinal axis of the surgical device away from the surgicaldevice's distal end where the desired operation is performed.

According to some embodiments, an elongated shaft assembly extendsdistally from a handle of a surgical instrument. The elongated shaftassembly includes an articulable portion that may articulate in at leastone direction between a first position, which may correspond to anon-articulated configuration, to a second position, which maycorrespond to a fully articulated configuration in which the distal tipis oriented at an angle (e.g., an articulation angle) relative to aportion of the elongated shaft assembly located proximal to thearticulable portion. When in the non-articulated, or straightconfiguration, a longitudinal axis passing through the articulableportion may be aligned with a longitudinal axis of the proximal portionof the elongated shaft assembly. Correspondingly, when in the fullyarticulated configuration, the distal tip of the elongated shaftassembly, and the longitudinal axis of the articulable portion, isoriented at an articulation angle relative to the longitudinal axis ofthe proximal portion. In one embodiment, the articulation angle of thefully articulated configuration may be between −30 degrees and 30degrees, between −45 degrees and 45 degrees, between −90 degrees and 90degrees, between −180 degrees and 180 degrees, between 15 degrees and 90degrees, or between 45 degrees and 90 degrees, though it should beunderstood that the current disclosure is not limited to any particularrange of articulation angles. Moreover, in some embodiments, thearticulable portion may be movable to one or more additional articulatedpositions between the non-articulated (i.e., straight) configuration andthe fully articulated configuration.

The surgical devices described herein may be made out of any desirablematerial or combination of materials. In some instances, the surgicaldevices described herein may be made from materials that are eithersterilized and/or are sterilizable using any appropriate methodincluding, but not limited to, heat, radiation, and/or pressure.Moreover, the materials may be capable of either being sterilizedbefore, during, or after assembly and packaging to maintain sterility.

In one embodiment, a surgical instrument may include an elongated shaftassembly including a first articulating shaft and a second articulatingshaft coaxially arranged relative to the first articulating shaft. Thefirst and second articulating shafts may include flexible portions thatform an articulable portion of the elongated shaft assembly, and thefirst and second articulating shafts are axially fixed relative to oneanother at a location distally located relative to the articulableportion. Proximal portions of the first and second articulating shaftsmay be displaceable relative to one another to move the articulableportion of the elongated shaft assembly between the first and secondpositions. For example, the proximal portions of the first and secondarticulating shafts may be displaced relative to one another toselectively place the first and second articulating shafts in opposingstates of tension and/or compression. As discussed in more detail below,such tensile and/or compressive forces may be transmitted through asuitable structure in the articulable portion to apply and/or release abending moment in the first and second articulating shafts, therebymoving the articulable portion between the non-articulated andarticulated configurations. In some embodiments, the bending momentcauses the articulable portion to move from the non-articulatedconfiguration, which may correspond to a relaxed configuration of theelongated shaft assembly, to the articulated configuration. However, itshould be understood that the current disclosure is not limited toembodiments in which a bending moment causes movement towards anarticulated configuration. For example, in some embodiments, the fullyarticulated configuration may correspond to a relaxed (i.e.,stress-free) state for the elongated shaft assembly, and application ofa bending moment (or other suitable stresses) may cause the elongatedshaft assembly to move toward the non-articulated (i.e., straight)configuration.

According to some aspects of the current disclosure, undesirablemovement of a distal tip of an elongated shaft assembly may be reducedby displacing first and second articulating shafts of the elongatedshaft assembly in opposing directions to move an articulable portion ofthe elongated shaft assembly between a non-articulated configuration andan articulated configuration. As discussed above, the first and secondarticulating shafts may be axially fixed at a location located distallyrelative to the articulable portion, and such opposing displacements ofthe proximal portions of the first and second articulating shafts maygive rise to opposing tensile and compressive forces in the articulatingshafts when moving the articulable portion between the non-articulatedand articulated configurations. Without wishing to be bound by theory,these opposing displacements of the shafts may help to reduce axialdisplacement of the distal tip in excess of that expected from simplyarticulating the elongated shaft assembly.

In one embodiment, a surgical instrument may include an articulationcontrol operable by a user to selectively move an articulable portion ofan elongated shaft assembly of the device between non-articulated andfully articulated configurations. Additionally, the surgical instrumentmay include an articulation lock that is movable between a first lockedconfiguration, in which the articulation lock prevents articulation ofthe articulable portion, and a second unlocked configuration, in whichthe articulation lock permits articulation. In some embodiments, thearticulation control also may be associated with the articulation locksuch that movement of the articulation control moves the articulationlock between the locked and unlocked positions. For example, in oneembodiment, the articulation control may be movable from a firstposition, which may correspond to the articulable portion being in thenon-articulated configuration and the articulation lock being in thelocked configuration, to a second position corresponding to thearticulation lock being moved to the unlocked position and thearticulable portion remaining in the non-articulated configuration. Thearticulation control may be further movable from the second position tothe third position, corresponding to the articulable portion being fullyarticulated. In this manner, a single articulation control may be usedfor both unlocking articulation of the articulable portion as well asfor controlling the articulation

Although embodiments described herein may include a single articulationcontrol that controls both articulation of an articulable portion of anelongated shaft assembly and movement of an articulation lock, it shouldbe understood that other arrangements may be suitable. For example, insome embodiments, a surgical instrument may include a separate lockcontrol for moving the articulation lock between the locked and unlockedpositions. Accordingly, it should be understood that the currentdisclosure is not limited to any particular arrangement of articulationand/or lock controls to move an articulable portion of an elongatedshaft assembly and/or articulation lock.

Depending on the embodiment, an articulable portion of an elongatedshaft assembly may be formed by one or more flexible portions of theassociated shafts that permit articulation. For example, the flexibleportions of the shafts may include a plurality of cuts extending in atransverse direction across a width of the shafts and arranged along atleast a portion of the length of the various shafts comprising theelongated shaft assembly to provide a desired flexibility. In someembodiments, the cuts may define a preferential bending direction forthe articulable portion, and articulating the articulable portion mayinvolve bending the articulable portion along the preferential bendingdirection. Although articulable portions including cuts are describedherein, other structures to permit articulation are also contemplated.For example, the articulable portion may include one or more weakenedsections arranged to create a desired flexibility and/or preferredbending direction, interconnected flexible segments, interconnectedsegments connected by hinges, one or more flexible shafts, or any othersuitable structure, as the disclosure is not limited in this regard.

As discussed above, it may be beneficial to provide a desired rigidityof the elongated shaft assembly while still permitting articulation ofan articulable portion of the elongated shaft assembly. Accordingly, insome embodiments, the specific dimension and arrangement of the cuts,spines, and/or other suitable features of at least first and secondarticulating shafts of the elongated shaft assembly may be selected toprovide the desired stiffness. In one embodiment, the first and secondspines may have a tapered configuration with distal portions of thefirst and second spines being narrower than proximal portions thereof.This may provide an increased bending stiffness of the elongated shaftassembly at a proximal end of the spines and increased flexibility ofthe assembly at the distal end. Such a configuration may permit thedistal end of the articulating shaft assembly to have enough flexibilityto articulate to a desired articulated position while also becomingprogressively stiffer at the proximal end of the articulable portion.Without wishing to be bound by theory, such a configuration may help toavoid undesired deflection of an elongated shaft assembly during use,for instance, when a user presses a distal end of the shaft assemblyagainst a surface to deploy a fastener into tissue.

In addition to the above, the inventors have recognized that the number,size, and/or spacing of the cuts in the shafts of an articulable portionof an elongated shaft assembly may influence the resulting stiffness ofthe elongated shaft assembly in the non-articulated and/or articulatedconfigurations. For example, the inventors have found that articulatingshafts having increased numbers of cuts and smaller cut sizes in thearticulable portion may provide for enhanced stiffness while stillpermitting a desired amount of articulation of the articulable portion.Accordingly, in some embodiments the number of cuts, the cut size,and/or cut spacing may be selected to provide a desired stiffness forthe elongated shaft assembly. Specific sizings and spacings of the cutsare discussed in more detail below in regards to specific embodiments.Moreover, in some embodiments, at least a portion of the cuts mayinclude stress reliefs at opposing ends of each cut to help reducestress concentrations along the cuts. The stress reliefs may have anysuitable shape including, for example, elliptical, circular, or anyother appropriate shape.

As noted above, an elongated shaft assembly may include first and secondarticulating shafts that are placed in opposing states of tension andcompression when an articulable portion of the elongated shaft assemblyis in an articulated configuration. In some embodiments, thearticulating shaft that is placed in the compressive state may include aplurality of cuts that are sized and shaped such that opposing sides ofeach of the cuts come into contact with one another when the articulableportion is fully articulated. For example, the inventors haveappreciated that such configurations may impart additional stabilityand/or rigidity to a distal portion of the elongated shaft assembly whenin the articulated configuration.

For the sake of clarity, the currently disclosed embodiments discussedbelow in regards to the figures are directed to a laparoscopic devicefor deploying one or more fasteners. However, the current disclosure isnot limited to laparoscopic devices for deploying one or more fasteners.Instead, the disclosed articulation systems, locking mechanisms,controls, and surgical fasteners may be used in any appropriate surgicalinstrument including an articulable portion. For example, appropriatesurgical instruments may include an endoscopic device, a borescopicdevice, a catheter, a surgical instrument for use in “open” procedures,or any other appropriate surgical instrument. Further, the disclosedsurgical instruments may include any appropriate end effector and arenot limited to the deployment of fasteners. However, in thoseembodiments including fasteners, the instrument including thearticulation locking mechanism may be loaded with one or more fasteners,or it may be constructed to allow the user to load the instrument withone or more fasteners. In addition, disclosed embodiments that includefasteners are described with regards to a generic fastener.Consequently, it should also be understood that any appropriate fastenermight be used with the currently disclosed articulation lockingmechanisms including a tack, a clip, a staple, a pin, a tissue anchor, abone anchor, or any other appropriate type of fastener.

Turning to the figures, specific non-limiting embodiments are describedin further detail. It should be understood that the various systems,components, features, and methods described relative to theseembodiments may be used either individually and/or in any desiredcombination as the disclosure is not limited to only the specificembodiments described herein.

FIG. 1 depicts one embodiment of a surgical instrument 2. The surgicalinstrument includes a handle 4 and an elongated shaft assembly 6extending distally from the handle toward a distal end 20, from whichfasteners may be deployed. The elongated shaft assembly 6 includes anarticulable portion 8 that is moveable between a non-articulated (i.e.,straight) position, and one or more articulated (i.e., curved or bent)positions. Articulation of the articulable portion 8 may be controlledby an articulation control 10, such as a rotatable and/or axiallydisplaceable knob, handle, lever, or other feature which may be movedrelative to the handle 4 between one or more positions to move thearticulable portion 8 between the non-articulated configuration and theone or more articulated configurations. The surgical instrument 2 alsoincludes a trigger 12 for actuating a fastener deployment system todeploy a fastener, though other appropriate types of actuation systemsto perform other types of operations are also contemplated.

The articulable portion 8 of the elongated shaft assembly may be movedbetween at least a first position, such as an unarticulated (i.e.straight) position, and second position, such as a fully articulatedposition, using the articulation control 10. Depending on theembodiment, the articulable portion 8 may be moved to one or morepreselected articulation angles, or the articulable portion 8 may beadjusted to one or more arbitrary (i.e. not preselected) articulationangles. The articulable portion 8 may be articulated in at least a firstdirection, though embodiments in which the articulable portionarticulates in at least a second direction are also envisioned. Forexample, the articulable portion 8 may be articulated in a firstdirection corresponding to an articulation angle greater thanapproximately 0° and in an opposing second direction corresponding to anarticulation angle less than approximately 0°. Alternatively, or inaddition to the above, the articulable portion 8 might be articulatedabout two different axes (e.g. articulation in the horizontal directionand the vertical direction) such that it articulates in at least twodirections.

In some embodiments, it may be desirable to rotate the elongated shaftassembly 6 to facilitate positioning of the distal tip. For example, theelongated shaft assembly 6 may simply be adapted to be rotatablerelative to at least a portion of the handle 4. Alternatively, a portionof the handle 4 including the elongated shaft assembly 6 may berotatable relative to another portion of the handle 4, such as theportion including the grip. One such embodiment is depicted in FIG. 1.In the depicted embodiment, the surgical instrument 2 includes a firsthandle portion 14 and a second handle portion 16 from which theelongated shaft assembly 6 extends. The first and second handle portions14 and 16 may be constructed and arranged in any appropriate fashion tobe rotatable relative to one another. The surgical instrument mayinclude a rotation lock 18 that is movable to selectively permit andprevent rotation of the second handle portion 16 relative to the firsthandle portion 14. It should be understood that while a surgicalinstrument including a rotatable elongated shaft assembly 6 or handle 4is depicted in the figures, a surgical instrument including a unitaryhandle and/or an elongated shaft assembly 6 that is stationary relativeto the handle are also possible as the current disclosure is not limitedin this manner.

In certain applications, it may be advantageous to include a distalrigid straight portion 20 that is distally located from the articulableportion 8 of the elongated shaft assembly. The rigid straight portion 20may include a number of features to aid in the deployment of fastenersfrom the distal end of the elongated shaft assembly 6. For example, thedistal rigid straight portion 20 may include fastener retaining elementssuch as tabs to retain a distal most fastener in a fastener deploymentposition prior to actuation of the surgical instrument. Additionally,without wishing to be bound by theory, when a driveshaft of a fastenerdeployment system applies a force to a fastener as it goes around anarticulated portion of the elongated shaft assembly, the force appliedby the drive shaft to the head of the fastener may not be fully alignedwith the deployment direction of the associated fastener. For example, adistal-most fastener may be located distally relative to a distal end ofthe driveshaft, and correspondingly, the fastener may be located withina portion of the elongated shaft assembly that is oriented at an anglethat is larger than a portion of the elongated shaft assembly containingthe distal end of the drive shaft. Consequently, when the drive shaftapplies a force to the fastener (e.g., via reciprocal movement of thedriveshaft), the force applied to the fastener may be misaligned with alongitudinal axis of the fastener.

In view of the foregoing, it may be desirable to include the distalrigid straight portion 20 to provide a straight portion of the elongatedshaft assembly with a sufficient length to accommodate a fastener and topermit the actuation force from the fastener deployment system to beapplied to that fastener in the same direction as the fastenerdeployment direction. Without wishing to be bound by theory, this mayresult in reduced actuation forces required to deploy a fastener fromthe surgical instrument. In some embodiments, the length of the distalrigid straight portion may be equal to or greater than a length of afastener such that the distal end of the driveshaft may be aligned inthe deployment direction. For example, as illustrated in FIG. 3, thedistal rigid straight portion 20 is longer than the length of thefasteners 202. In this manner, both a distal-most fastener and thedistal end of the driveshaft may be received in the distal rigidstraight portion to aid in aligning the deployment force from thedriveshaft with the orientation of the fastener. While a surgicalinstrument 2 including a distal rigid straight portion 20 has beendescribed herein, and depicted in the figures, it should also beunderstood that embodiments are envisioned in which the articulableportion 8 extends all the way to the distal end of the elongated shaftassembly 6 such that the surgical instrument does not include a distalrigid straight portion.

FIG. 2 is a schematic side view of the surgical instrument of FIG. 1,showing the various components and systems that may be provided withinthe handle 4. As illustrated, the trigger 12 may be coupled to a returnspring 22, which may provide a restoring force to urge the trigger backtowards an unactuated position following actuation of the trigger todeploy a fastener. The trigger may be coupled to a drive system 24constructed and arranged to apply a deployment force to a fastener uponactuation of the trigger 12 to deploy the fastener from the distal endof the elongated shaft assembly 6. Moreover, in some embodiments, thesurgical instrument may include an actuation lockout system 26 that mayselectively prevent activation of the drive system 24 until a forceapplied to the trigger exceeds a threshold force. Although a specificdrive system and actuation lockout system are shown in the figures, itshould be understood that the current disclosure is not limited tosurgical instruments including any particular drive systems and/oractuation lockout systems. For example, any appropriate arrangement ofcams, linkages, gears, clutches, and other appropriate components may beused in any appropriate combination as part of a drive system.

In some embodiments, a surgical instrument may include a plurality offasteners within the elongated shaft assembly 6, and the fasteners maybe deployed sequentially upon subsequent actuations of the trigger 12.In some such embodiments, it may be desirable to monitor the number offasteners remaining within the elongated shaft assembly that have notyet been deployed. Accordingly, the surgical instrument 2 may include afastener level indicator system 28 that is constructed and arranged toprovide an indication of the number of fasteners available fordeployment. For example, the fastener level indicator system 28 may becoupled to the trigger 12 such that upon actuation of the trigger (anddeployment of a fastener), the fastener level indicator system may movea corresponding indicator to indicate that the number of fastenersremaining has decreased by one (e.g., see FIGS. 21-23 detailed furtherbelow). However, it should be understood that other systems formonitoring the number of remaining fasteners also may be used, and thatthe surgical instrument may not include a fastener level monitoringsystem in some embodiments, as the disclosure is not limited in thisregard.

In addition to the above, FIG. 2 depicts an articulation control system100 according to some embodiments. As described in more detail below,the articulation control system is coupled to the articulation control10 and one or more shafts of the elongated shaft assembly 6 such thatmoving the articulation control 10 applies a suitable articulation forceto the one or more shafts, or other component of the elongated shaftassembly, to selectively move the articulable portion 8 of the elongatedshaft assembly between at least an unarticulated and an articulatedposition.

FIG. 3 depicts an exploded view of the elongated shaft assembly 6 of thesurgical instrument 2 which extends distally from the handle 4. Theelongated shaft assembly includes a drive shaft 30, which may be drivenby a suitable drive system (such as drive system 24 discussed above) toapply a distally directed force to a fastener to deploy the fastenerfrom the distal end of the elongated shaft assembly. The elongated shaftassembly further includes a first articulating shaft 32, which may be aninner articulating shaft, a second articulating shaft 34, which may bean outer articulating shaft, and an articulation lock in the form of alocking shaft 36. As described in more detail below, the first andsecond articulating shafts are constructed and arranged to apply anarticulation force to the elongated shaft assembly to move thearticulable portion 8 between the non-articulated position and the oneor more articulated positions.

As illustrated in FIG. 3, the various shafts of the elongated shaftassembly may be arranged coaxially relative to one another. Forinstance, in the depicted embodiment, the fastener carrier and followerassembly 38 is received within the driveshaft, which is received withinthe first and second articulating shafts 32, 34 and locking shaft 36.Although a particular arrangement of shafts is shown in the figures, itshould be understood that other arrangements also may be suitable. Forexample, in one embodiment, the locking shaft 36 may be located withinthe first and second articulating shafts 32, 34. Accordingly, thecurrent disclosure is not limited to any specific arrangement of shaftscomprising the elongated shaft assembly.

In some embodiments, a fastener carrier and follower assembly 38 isprovided within an elongated shaft assembly. For example, a stack 200 offasteners may be slidably disposed on a fastener carrier. The followermay be located proximally relative to the fastener stack 200 and mayapply a distally directed force to one or more surgical fasteners of thestack to urge the stack of fasteners in the distal direction.Appropriate types of followers include, but are not limited to,compressed springs, ratchet and pawl mechanisms, walking beamassemblies, and/or any other appropriate type of mechanism capable ofmoving the stack of fasteners in a distal direction toward a distal endof the device.

FIG. 4 shows an exploded perspective view of a first articulating shaft32, second articulating shaft 34, and locking shaft 36. Each of theseshafts may include a flexible portion located in the articulable portion8 of the elongated shaft assembly. As illustrated, the flexible portionsinclude a plurality of cuts which define one or more spines extendingalong a length of the shafts in the articulable portion. In particular,the first articulating shaft 32 includes a first plurality of cuts 40extending in a transverse direction partially around a circumference ofthe first articulation shaft and are spaced from one another along alength of the shaft to define a first spine 44 extending along a lengthof the flexible portion of the first articulating shaft. Similarly, thesecond articulating shaft 34 includes a second plurality of cuts 42extending in a transverse direction partially around a circumference ofthe second articulation shaft and are spaced from one another along alength of the shaft to define a second spine 46. The cuts 40, 42 andspines 44, 46 may define respective preferential bending directions forthe first and second articulating shafts 32 and 34 oriented in adirection that is perpendicular to a direction in which the spinesextend. For example, the first articulating shaft 32 has a preferredbending direction 48 and the second articulating shaft 34 has apreferred bending direction 50. In the depicted embodiment, the bendingdirections 48 and 50 are parallel, but the first and second spines 44,46 are located on opposing sides of the elongated shaft assembly. Asdiscussed in more detail below, such a configuration may result in thefirst and second articulating shafts bending in the same direction whenthe first and second articulating shafts are placed in opposing statesof tension and compression.

Depending on the particular embodiment, the first and secondarticulating shafts may include any suitable structure to providedesired preferential bending directions. For example, as discussedabove, the first and second articulating shafts may include spinespositioned opposite one another to define parallel preferential bendingdirections for the first and second articulating shafts. In someembodiments, the first and second spines may be parallel to alongitudinal axis of the elongated shaft assembly, though otherconfigurations are also contemplated. For example, the first and secondspines may extend helically around opposing sides the first and secondarticulating shafts, respectively. Accordingly, it should be understoodthat the first and second spines may be arranged in any suitable manner.

In addition to the cuts and spines on the articulating shafts, thelocking shaft 36 may include two sets of cuts 54 which define opposingspines 56 extending along at least a portion of a length of the lockingshaft and along a length of the flexible portion. In this manner, thecuts 54 and spines 56 define a preferential bending direction 58 that isperpendicular to a plane passing between the opposing spines as well asa direction of bending resistance 60 in a direction extending betweenthe opposing spines. In some embodiments, the locking shaft 36 isrotatable in direction 52 about a longitudinal axis of the elongatedshaft assembly and relative to the first and second articulating shafts32, 34. For example, locking shaft may be rotated to an unlockedposition in which the preferential bending direction 58 of the lockingshaft is aligned with the preferential bending directions 48, 50 of thefirst and second articulating shafts to permit articulation of thearticulable portion 8 of the elongated shaft assembly 6. Similarly, thelocking shaft may be rotated to a locked position in which the directionof bending resistance 60 is aligned with the preferential bendingdirections of the articulating shafts to inhibit or preventarticulation. Moreover, and similar to the spines on the first andsecond articulating shafts, the spines 56 may be arranged in anysuitable manner on the locking shaft, such as parallel to a longitudinalaxis of the elongated shaft assembly, at an angle relative to thelongitudinal axis, helically around opposing sides of the locking shaft,and so on.

While several possible embodiments including an articulation lock in theform of a locking shaft rotatable relative to first and secondarticulating shafts are described herein, other arrangements for thearticulation lock are contemplated. For example, the articulation lockmay include a locking shaft that is axially movable relative to thearticulating shafts to move the locking shaft between locked andunlocked configurations. The locking shaft may include a flexibleportion, and the axial movement may selectively align or overlap theflexible portion of the locking shaft with an articulable portion of anelongated shaft assembly to permit articulation. When the flexibleportion is not aligned with the articulable portion, the locking shaftmay inhibit articulation of the articulable portion. Accordingly, itshould be understood that the current disclosure is not limited to anyparticular structures for an articulation lock to selectively permit andprevent articulation of the elongated shaft assembly.

As shown in FIG. 5, the first and second articulating shafts 32 and 34may be attached to one another at an attachment point 62, which islocated distally from the articulable portion of the elongated shaftassembly. This attachment may axially fix the first and secondarticulating shafts to one another at the attachment point. In thedepicted embodiment, the attachment point is located at the distal endof the second articulating shaft 34, though other configurations alsomay be suitable. For example, the second articulating shaft may extendbeyond the attachment point such that the attachment point is spacedfrom the distal end of the second articulating shaft. Moreover, itshould be understood that the first and second articulating shafts maybe attached in any suitable manner, such as with an adhesive, one ormore fasteners, one or more pins, one or more welds, and/or any otherappropriate form of connection.

Due to the attachment of the first and second articulating shafts 32, 34at the distally located attachment point 62, application of axial forcesand/or displacements to corresponding proximal portions of the first andsecond shafts may place the first and second shafts in a state oftension and/or compression. For example, a proximally directed force anddisplacement 64 applied to a proximal portion of the first articulatingshaft 32 may create a tensile stress in the first articulating shaft.Similarly, application of a corresponding distally directed force anddisplacement to a proximal portion of the second articulating shaft 34may create a compressive stress in the second articulating shaft. Theseopposing tensile and compressive stresses are transmitted through theopposing spines 44 and 46 of the first and second articulating shaftswhich are both offset from a neutral bending axis of the overallelongated shaft assembly. This creates a bending moment in thearticulating shafts which causes the articulating shafts to bend alongdirection 68 to move the elongated shaft assembly toward an articulatedposition. It should be understood that the proximally and distallydirected forces and displacements may be applied to the first and secondshafts, respectively, via any suitable articulation control system, asdiscussed in more detail below.

Although a particular arrangement of forces and/or displacements appliedto the first and second articulating shafts are shown in the figures anddescribed above to move the elongated shaft assembly toward thearticulated position, other arrangements also may be suitable. Forexample, in some embodiments, articulating the elongated shaft assemblymay involve applying a distally directed force and/or displacement tothe proximal portion of the first articulating shaft 32 and a proximallydirected force and/or displacement to the proximal portion of the secondarticulating shaft 34 which would cause the elongated shaft assembly toarticulate in the opposite direction to that shown in FIG. 5.Alternatively, in certain embodiments, the first and second articulatingshafts may form an elongated shaft assembly with a resting shape (i.e.,when no stresses are applied) that is curved (e.g., along a directioncorresponding to an articulated configuration), and the first and secondarticulating shafts may be placed into opposing states of tension andcompression to move the elongated shaft assembly to the non-articulated(i.e., straight) configuration. Accordingly, it should be understoodthat the currently disclosed articulating shaft assemblies are notlimited with regards to what direction they articulate and/or the finalconfiguration they are in when placed into a state of compression and/ortension.

While several possible embodiments related to the construction of thearticulable elongated shaft assembly are described herein, it should beunderstood that the current disclosure is not limited to only thedescribed embodiments. For example, the articulable portion of anelongated shaft assembly may be constructed and arranged in anyappropriate fashion to provide articulation in a desired direction.Further, while a specific type of articulation mechanism usingarticulating shafts with opposing spines is described, other mechanismsfor articulating an elongated shaft assembly may be suitable. Forexample the articulable portion of the elongated shaft assembly may bearticulated using: one or more control wires, ribbons, or slatsassociated with the articulable portion; pre-stressed members andretractable sheaths, rigid linkages associated with pivot joints; or anyother appropriate structure capable of articulating the articulableportion.

As discussed previously, a surgical instrument may include anarticulation control to selectively move an articulable portion of anelongated shaft assembly between the non-articulated and articulatedpositions. Depending on the particular embodiment, the articulationcontrol may be coupled to articulating shafts of the elongated shaftassembly via any suitable structure to control the articulation .Referring to FIGS. 6-14, embodiments of an articulation control system100 are described in more detail.

FIG. 6 is a schematic side view of an articulation system 100 in a firstposition, which may correspond to the elongated shaft assembly being inthe non-articulated (straight) configuration. The articulation systemincludes an articulation cam 102 that is coupled to the articulationcontrol 10, such that movement of the articulation control 10 causesassociated movement of the articulation cam 102. In the depictedembodiment, rotational movement of the articulation control causes thearticulation cam to rotate relative to an associated portion of thehandle including, for example, a rotatable handle portion 16 of thesurgical instrument. While rotation has been illustrated, it should beunderstood that other types of movement including, for example,translational movement of the articulation control and articulation camare also envisioned as the current disclosure is not limited to arotatable articulation cam.

In the depicted embodiment, the articulation cam 102 includes first andsecond cam profiles 104 and 106 which may be located on opposing sidesof a rotational axis of the cam. The cam profiles may be constructed andarranged to receive first and second articulation pins 108 and 110,respectively. The first and second articulation pins may be coupled torespective proximal portions of the first and second articulatingshafts, such that movement of the articulation pins within the camprofiles displaces the proximal portions of the articulating shafts. Forexample, as discussed in more detail below, each of the cam profiles 104and 106 may include one or more profile portions located at differentradial distances from the rotational axis of the articulation cam 102.Consequently, rotation of the articulation cam may move the pins betweenthe profile portions located at different radial distances to displacethe associated proximal portions of the articulating shafts. Whileembodiments including articulation pins coupled to cam profiles aredescribed herein, it should be understood that other structures tocouple the articulating shafts to the articulation cam also may besuitable, as the current disclosure is not limited in this regard.

In addition to controlling articulation of the articulating shaftassembly, the articulation control system 100 may also be used to movean associated locking shaft 36 between locked and unlocked positions toselectively inhibit or permit articulation of the elongated shaftassembly. In the depicted embodiment, the articulation cam 102 iscoupled to a locking cam 112, which is in turn coupled to the lockingshaft 36 via a gear 114. As discussed in more detail below, movement ofthe articulation cam (e.g., rotational movement) may correspondinglydisplace the locking cam, which may rotate the gear 114. Rotation ofgear 114 may then rotate the locking shaft 36 to move the locking shaftbetween locked and unlocked configurations as discussed previouslyabove.

In some embodiments, it may be desirable for an articulation controlsystem to include one or more features to aid in maintaining anelongated shaft assembly in the non-articulated position or in one ormore articulated positions. For example, one or more detent mechanismsor other appropriate form of lock may help to avoid undesired movementof the articulation control system and/or undesired movement of theelongated shaft assembly toward or away from the articulated position.In the depicted embodiment, the articulation control system may includefirst and second cam locks 116 and 118 corresponding to resilient armsextending out from the articulation cam 102. Corresponding features,such as recesses 120 and 122, are provided on an interior surface of therotatable handle portion 16, and engagement of the cam locks 116, 118with the recesses 120, 122 may function as a detent mechanism tomaintain the articulation cam 102 in a desired orientation. For example,as shown in FIG. 6, engagement of the first cam lock 116 with recess 120maintains the articulation control system in the first position tomaintain the elongated shaft assembly in the non-articulated position.Similarly, as shown in FIG. 12, engagement of the second cam lock 118with the second recess 122 may aid in maintaining the elongated shaftassembly in the fully articulated position. When movement of thearticulation control is desired, the resilient arms may deform to allowthe cam locks to disengage from the corresponding recesses.

Although embodiments including two cam locks and two associated recessescorresponding to the non-articulated and fully articulated positions forthe elongated shaft assembly have been depicted, it should be understoodthat the articulation control system may include any suitable numberand/or type of cam locks. For instance, in some embodiments, one or moreadditional cam locks and recesses may be provided to maintain thearticulation control system at one or more intermediate positions, whichmay correspond to a partially articulated position for the elongatedshaft assembly. In other embodiments, the articulation control systemmay not include any cam locks. For instance, frictional engagementbetween the various components of the articulation control system may besufficient to maintain the articulation control at a desired position,or the articulation control system may be held at a desired position viauser input to the articulation control 10.

As discussed previously, in some embodiments, it may be desirable for anarticulation control system to apply opposing displacements to proximalportions of first and second articulating shafts. For example, suchopposing displacements may place the first and second articulatingshafts in opposing states of tension and/or compression (e.g., due tothe shafts being axially fixed at a distally located attachment point),which may reduce motion of a distal tip of the elongated shaft assemblyduring articulation of the articulable portion of the surgicalinstrument. Accordingly, the various cam profiles of the articulationcam may be shaped to provide this desired motion for the proximalportions of the articulating shafts, as discussed below.

For example, FIG. 7 shows a schematic side view of the articulation cam102 of the articulation control system 100. As illustrated, the firstcam profile 104 includes a first profile portion 124 and a secondprofile portion 126. Similarly, the second cam profile 106 includes athird profile portion 128 and a fourth profile portion 130. The firstand third profile portions follow curved paths, which may be at constantradial distances from a rotational axis of the articulation cam. In someembodiments, the first and third profile portions may be located at aconstant first radial distance from the rotational axis.Correspondingly, the second and fourth profile portions follow curvedpaths located at radial distances different from the radial distance ofthe corresponding first and third profile portions. For example, thesecond and fourth profile portions may extend to a second larger radialdistance from the rotational axis. In this manner, when the first andsecond articulation pins 108 and 110 associated with proximal portionsof first and second articulating shafts (not shown in FIG. 7) are movedwithin the first and second cam profiles 104 and 106, respectively, thearticulation pins are displaced relative to the rotational axis of thearticulation cam. Since the articulation pins and articulating shaftsare constrained to moving in the axial direction, this results in axialdisplacement of the pins and shafts towards and/or away from arotational axis of the articulation cam depending on the direction ofrotation.

While embodiments are described herein in which an articulation camincludes cam profiles with multiple profile portions, it should beunderstood that the disclosure is not limited in this manner, and thatthe cam profiles may have any suitable configuration such that the camprofiles cause a desired movement of the proximal portions of thearticulating shafts in opposing directions.

In the depicted embodiment, the first and second cam profiles 104 and106 are arranged symmetrically about the rotational axis of thearticulation cam 102. Therefore, the first and second articulation pins108 and 110, and associated articulating shafts 32 and 34, are displacedin opposing directions upon rotation of the articulation cam, see FIGS.11-14. Additionally, the various portions of the first and second camprofiles 104 and 106 may be located at the same radial distances fromthe rotational axis of the articulation cam 102 which causes the firstand second articulation pins 108 and 110, and associated articulatingshafts 32 and 34 to be displaced by equal magnitudes in the opposingdirections.

While a particular arrangement of the cam profiles has been illustratedit should be understood that other configurations may be suitable. Forexample, the cam profiles may not be symmetrically arranged around arotational axis of the cam. In such an embodiment, the first profileportion 124, second profile portion 126, third profile portion 128, andfourth profile portion 130 may each be spaced at different radialdistances from the rotational axis of the articulation cam 102. In otherembodiments, one or both of the cam profiles may have only a singleprofile portion in which the spacing of the profile portion from therotation axis varies along the length of the profile, or the camprofiles may have more than two profile portions as the disclosure isnot so limited. Moreover, depending on the particular embodiment, thefirst, second, third, and/or fourth path portions of the first andsecond cam profiles may be located at respective constant radialdistances from the rotational axis of the articulation cam, or theradial distances may not be constant and may vary within the respectivepath portions.

As best illustrated in FIG. 8, the articulation cam may be constructedand arranged to accommodate various other components of a surgicalinstrument. For example, the articulation cam may include one or morechannels, openings, or other feature to accommodate components of apower transmission system or a fastener deployment system that extendfrom a proximal portion of the device towards a distal end of anelongated shaft assembly. In the depicted embodiment, the articulationcam 102 includes a pair of end pieces 134 attached to one another withcross pieces 136 which define a channel 138 extending through thearticulation cam. Each of the end pieces may include identical camprofiles 104 and 106. Additionally, the articulation cam may include arotation shaft 140 extending from the end pieces that may include akeyed coupling 142 to attach an articulation control 10, such as ahandle, to the articulation cam. However, other forms of attaching anarticulation control to the cam including, but not limited to, welds,fasteners, snap fits, adhesives, and/or other appropriate attachmentmethods are also contemplated as the disclosure is not so limited.

In some embodiments, an articulation cam may be formed as a singlemonolithic component, for example, via a suitable molding or castingprocess. However, embodiments in which the articulation cam is formedfrom separate elements are also contemplated. For example, the variouscomponents, such as the end pieces and cross pieces may be formedseparately and attached to one another with welds, fasteners, snap fits,adhesives, and/or other appropriate attachment methods as the disclosureis not so limited.

FIG. 9 shows a schematic side view of a locking cam 112, which may becoupled to an articulation cam 102 and the locking shaft 36 as shown inFIG. 6. The locking cam includes a locking cam profile 144 constructedand arranged to receive a locking pin 152 (see FIG. 10) which isreceived within a through hole 132 of the corresponding articulation cam102, see FIGS. 7-8. Accordingly, the locking pin 152 rotates at aconstant radial distance from the rotational axis of the articulationcam 102 when the articulation cam is rotated. The locking cam 112 may beconstrained to move in a desired direction, such as a directiontransverse to a longitudinal axis of the elongated shaft assembly, tomove the articulation lock to the unlocked configuration. Moreover, thelocking cam profile 144 may include a fifth profile portion 146constructed and arranged such that the rotational movement of thelocking pin within the fifth profile portion causes the locking cam tomove in the desired direction to displace the locking cam from a firstposition, which may correspond to the locking shaft 36 being in thelocked configuration, to a second position corresponding to the lockingshaft being in the unlocked configuration, see FIGS. 6 and 12. Forexample, in the depicted embodiment, the fifth profile portion islinear, though other configurations may be suitable.

The locking cam profile 144 of the locking cam 112 may further includesa sixth profile portion 148 that may be constructed and arranged suchthat movement of the locking pin 152 within the sixth profile portiondoes not cause any displacement of the locking cam. For example, thesixth profile portion may have a curved configuration such that, whenthe locking cam 112 is moved to the second position, the sixth profileportion 148 is located at a constant radial distance from the rotationalaxis of the articulation cam 102 that corresponds to the distance of thelocking pin from the rotational axis. In this manner, a first portion ofthe movement of the articulation cam may cause movement of the lockingcam, while the locking cam may remain stationary during a second portionof movement of the articulation cam.

In addition to the locking cam profile 144, the locking cam 112 mayinclude a rack 150 that is constructed and arranged to engage a gear 114which may be coupled to the locking shaft 36 of the elongated shaftassembly. The rack may extend in a direction that is parallel to adirection of movement of the locking cam. In this manner, displacementof the locking cam between the first position and the second position,may cause corresponding rotation of the gear and the locking shaft tomove the locking shaft between the locked and unlocked configurations aspreviously discussed.

FIG. 10 is a schematic exploded view of an articulation control system100, and illustrates how the various components of the articulationcontrol system may be coupled to one another. As shown in the figure,the first articulation pin 108 is coupled to a proximal portion and/orend of the first articulating shaft 32 via a first shuttle 154 that isconnected to the proximal portion and/or end of the first articulationshaft and first pin, and the second articulation pin 110 is coupled to aproximal portion and/or end of the second articulating shaft 34 via asecond shuttle 156 connected to the proximal portion and/or end of thesecond articulation shaft and second pin. The first and second shuttlesmay be received within the channel 138 of the articulation cam 102 suchthat opposing ends of the articulation pins extend out from the shuttlesand into the first and second cam profiles 104 and 106 located on eitherside of the articulation cam. Moreover, an end of a locking pin 152 ofthe articulation cam may extend out from, and in some embodiments,through the articulation cam such that the locking pin is received inthe locking cam profile 144 of the locking cam 112 to couple thearticulation cam to the locking cam.

FIGS. 6 and 11-14 depict various aspects of the operation of thearticulation control system 100. As discussed previously, FIG. 6 depictsthe articulation control system 100 in a first position, correspondingto the elongated shaft assembly being in the non-articulated positionand the locking shaft in the locked configuration. FIG. 11 shows aperspective view of the articulation control system in the firstposition, though for clarity, the articulation cam 102 is not depictedin FIG. 11. As illustrated, when the articulation control is in thefirst position, the first and second shuttles 154 and 156 may be locatedadjacent to one another and the locking pin 152 is received in a firstend of locking cam profile 144. Moreover, when the locking cam is in thefirst position, a top portion of the locking cam rack 150 may be engagedwith the gear 114.

FIGS. 12-13 shows schematic side views of the articulation controlsystem in a second position and a third position, respectively. Forexample, the second position may be an intermediate configurationcorresponding to the locking shaft 36 being rotated to the unlockedconfiguration, but prior to articulation of the elongated shaft assemblysuch that the elongated shaft assembly is still in the non-articulatedposition. As shown in the figure, the articulation cam has been rotatedrelative to the configuration shown in FIG. 6, resulting in movement ofthe locking pin 152 within the locking cam profile 144 to the end of thefifth path portion 146 (and to the beginning of the sixth path portion148). As discussed previously, movement of the locking pin within thefifth path portion may displace the locking cam 112 from the firstposition (shown in FIG. 6) to the second position shown in FIG. 12. Thismovement of the locking cam displaces the locking cam rack 150 whichrotates the gear 114 and associated locking shaft 36 in direction 160(FIG. 14). In the depicted embodiments, the displacement of the lockingcam is in a direction 158 (FIG. 14) that is transverse to thelongitudinal axis of the elongated shaft assembly, though otherdirections of movement and/or types of movement (such as rotationalmovement) also may be suitable, as the current disclosure is not limitedin this regard.

As also shown in FIG. 12, when the articulation control system 100 is inthe second configuration, the first and second articulation pins 108 and112 are moved within the first and third path portions 124 and 128 ofthe first and second cam profiles 104 and 106, respectively. However, insome embodiments, the first and third path portions are located atconstant radial distances from the rotational axis of the articulationcam. Thus, the articulation pins, and correspondingly, the elongatedshaft assembly 6, remain stationary relative to the handle duringmovement of the articulation control system from the first positionshown in FIG. 6 to the second position shown in FIG. 12. In this manner,moving the articulation control system from the first position to thesecond positon may move the locking shaft 36 from a locked configurationto an unlocked configuration while not applying any force to and/ordisplacing the articulating shafts which remain in the non-articulatedconfiguration.

FIGS. 13 and 14 show the articulation control system 100 in a thirdposition, where the locking shaft 36 is in the unlocked configurationand the elongated shaft assembly has been fully articulated. Asillustrated in FIG. 13, the articulation cam 102 is further rotatedrelative to the second position shown in FIG. 12. This rotation causesthe first and second articulation pins 108 and 110 to move within thefirst and second cam profiles 104 and 106 into the second and fourthprofile portions 126 and 130, respectively. Since the second and fourthprofile portions are located at different radial distances from therotational axis of the articulation cam 102 relative to the first andthird profile portions, the first and second articulation pins 108 and110 are displaced in opposing directions either away from, or towardsthe rotational axis of the articulation cam. In particular, as shown inFIG. 14, the second and fourth profile portions are located a largerradial distance from the rotational axis of the articulation camrelative to the first and third profile portions. Accordingly, the firstand second articulation pins 108 and 110, which may be constrained tomove only axially as discussed below, are displaced in opposing axialdirections. Specifically, the first articulation pin 108 is displaced ina proximal direction 162, and the second articulation pin is displacedin a distal direction 164. In some embodiments, the first and second camprofiles 104 and 106 may be arranged to cause displacements of the firstand second articulation pins 108 and 110 that are equal in magnitude,which may aid in avoiding movement of the distal tip of the elongatedshaft assembly, as discussed previously. However, in other embodiments,the displacements may not be equal in magnitude, as the disclosure isnot limited in this regard.

Since the first and second articulation pins 108 and 110 are coupled tothe proximal portions and/or ends of the first and second articulatingshafts 32 and 34 via the first and second shuttles 154 and 156,respectively, the displacement of the articulation pins causes anassociated displacement of the proximal ends of the articulating shafts.In particular the proximal end of the first articulating shaft 32 isdisplaced proximally along direction 162, and the proximal end of thesecond articulating shaft 34 is displaced distally along direction 164,see FIG. 14. Moreover, due to the attachment of the first and secondshafts at the distally located attachment point 62 (see FIG. 5), theopposing displacements of the first and second articulating shaftsplaces the shafts in opposing states of tension and compression,respectively. As discussed previously, these tensile and compressivestates create a bending moment in the articulating shafts that causesthe elongated shaft assembly to articulate toward the articulatedposition.

In addition to the movement of the articulation pins 108 and 110 withinthe second and fourth path portions 126 and 130, the locking pin 152 ismoved within the sixth path portion 148 when the articulation control100 is moved from the second position (FIG. 12) to the third position,see FIG. 13. However, as discussed above in connection with FIG. 9, whenthe locking cam is in the second position, which may correspond to thelocking shaft being in the unlocked configuration, the sixth profileportion 148 of the locking cam may be located at a constant radialdistance from the rotational axis of the articulation cam 102.Accordingly, movement of the locking pin within the sixth path portionmay not cause any further movement of the locking cam, or any associatedmovement (e.g., rotation) of the locking shaft. In this manner, thelocking shaft may remain in the unlocked position while the articulationcontrol is moved between the second and third positions to articulatethe elongated shaft assembly.

Although an articulation control system including various pins receivedin corresponding cam profiles is described above and shown in thefigures, other configurations are also contemplated. For example, thearticulation cam may include suitably shaped engaging surfaces thatengage with corresponding surfaces on the articulating shafts and/orlocking shaft to cause desired movement(s) of the shaft(s). Moreover,while a rotatable articulation cam is described above, other types ofmovement for the articulation cam may be suitable, as the currentdisclosure is not limited to surgical instruments in which anarticulation cam is rotated to control articulation. For example, incertain embodiments, movement of the articulation control may displacethe articulation cam relative to the handle of the surgical instrument,and the articulation may include suitably shaped camming structures tocause a desired displacement of the proximal portions of thearticulating shafts.

Moreover, it should be understood that the articulation control systemsdescribed herein that control both articulation of an elongated shaftassembly movement of an articulation lock may be used with any suitablearticulation system and/or locking system, as articulation controlsystems are not limited to the specific articulation and locking systemsdescribed herein. For example, the combined articulation andarticulation lock control system may be used with articulation systemsincluding elastically biased systems, flexible tubes and/or shafts,linked segments biased in one or more directions with one or moreflexible members or cables placed into tension, and so on.

Referring now to FIG. 15, the operation of one embodiment of anarticulation control system 100 and articulation lock described above inconnection with FIGS. 6-14 is described in more detail. In particular,FIG. 15 is a schematic plot of the angular position of a locking shaft36 as well as the articulation angle of the articulable portion of anelongated shaft assembly 6 relative to a proximal straight portion ofthe elongated shaft assembly as a function of the position of thearticulation control 10. For example, position A may correspond to thefirst position of the articulation control system as illustrated in FIG.6, i.e. an unarticulated position, in which the locking shaft is in thelocked configuration and the elongated shaft assembly is in thenon-articulated configuration. Correspondingly, position B maycorrespond to the second position of the articulation control systemillustrated in FIG. 12 where the elongated shaft assembly has beenunlocked and just prior to articulating the elongated shaft assembly.Position C may correspond to the third position of the articulationcontrol system illustrated in FIG. 13 once the device has been fullyarticulated.

As illustrated in FIG. 15, when the articulation control is moved fromposition A to position B, the locking shaft moves from the lockedconfiguration to the unlocked configuration. For example, in theembodiments described above in connection with FIGS. 6-14, the movementof the locking shaft may be a rotational movement. In particular, thelocked configuration at position A may correspond to 0° of rotation suchthat the direction of bending resistance of the locking shaft is alignedwith the preferential bending direction of the articulating shafts toprevent articulation of the elongated shaft assembly. Moving thearticulation control from position A towards position B causes thelocking shaft to rotate relative to the articulating shafts as describedpreviously. This rotation may align one or more of the preferentialbending directions of the locking shaft and articulating shafts to placethe locking shaft and elongated shaft assembly in the unlockedconfiguration. This rotation may correspond to any appropriate angle,but in some embodiments, the unlocked configuration at position B maycorrespond to the locking shaft being rotated 90° relative to the lockedconfiguration at position A.

While the locking shaft is moved from the locked position to theunlocked position during movement of the articulation control fromposition A to position B, the elongated shaft assembly does notarticulate and remains in the non-articulated position. Specifically,the articulation angle remains at an angle of θ_(non-articulated), whichmay correspond to an articulation angle of 0°. Depending on theembodiment, this may be achieved via one or more suitably shaped camprofiles associated with the articulating shafts, such as thosediscussed above, which include at least one path portion located at aconstant radial distance from a rotational axis or at a constant lineardistance relative to a translational axis of the articulation camdepending on the type of cam movement. Accordingly, the pins, and thusthe associated articulating shafts are not moved when the articulationcontrol is moved from position A to position B.

When the articulation control is moved from position B to position C,the locking shaft may remain stationary in the unlocked configuration.For example, in the embodiments described above in connection with FIGS.6-14, moving the articulation control handle from position B to positionC may correspond to movement of the locking pin within the sixth pathportion of the locking cam. As discussed previously, this portion of thelocking cam may be located a constant radial distance from therotational axis of the articulation cam when the locking cam is in thesecond position. As a result, moving the locking pin within this pathportion may not cause any associated movement of the locking cam and mayallow the locking shaft to remain in the locked position.

In addition to the above, moving the articulation control from positionB to position C may cause the elongated shaft assembly to articulatefrom θ_(non-articulated) to an angle of θ_(articulated), which in someembodiments, may correspond to the elongated shaft assembly being movedto a fully articulated position. The specific articulation angle maycorrespond to any appropriate angle as described above. In someembodiments, such as those described above in connection with FIGS.6-14, this articulation of the elongated shaft assembly may be caused bymovement of the articulation pins within respective second and fourthpath portions of the articulation cam, which are spaced a larger radialdistance from the rotational axis of the articulation cam compared tothe first and third path portions. Consequently, the articulation pins,and the associated proximal portions of the first and secondarticulating shafts, are displaced in opposing directions to place thearticulating shafts in opposing states of tension and compression,thereby creating a bending moment to move the elongated shaft assemblyto the articulated position. However, as discussed previously, otherarticulation mechanisms may be suitable, and correspondingly, moving thearticulation control from position B to position C may cause anelongated shaft assembly in any suitable manner.

Although the articulation angle of θ_(articulated) is depicted in FIG.15 as being smaller in magnitude than the angle corresponding to thelocking shaft being in the unlocked position (e.g., 90°), otherarrangements are also envisioned. For example, in some embodiments, thearticulation angle of the elongated shaft assembly may be larger thanthe rotation angle required to move the locking shaft from the lockedconfiguration to the unlocked configuration. Moreover, while the lockingshaft rotation and elongated shaft assembly articulation are depicted asvarying linearly with movement of the articulation control, the responsemay have any suitable functional form and may not be linear in someembodiments. In addition to the above, while in FIG. 15 there is nooverlap in movement of the locking shaft and articulation of theelongated shaft assembly, other arrangements may be suitable. Forexample, in some embodiments, the elongated shaft assembly may beginarticulating before the locking shaft is in the fully unlockedconfiguration as the disclosure is not so limited..

Referring now to FIGS. 16-18, various aspects of the locking shaft 36and the first and second articulating shafts 32 and 34 are described inmore detail.

FIG. 16 depicts a schematic side view of a distal portion of a lockingshaft 36. The locking shaft includes a pair of spines 56 located onopposing sides of the locking shaft (only one spine is depicted in FIG.16) and the spines extend along the length of a flexible portion 70 ofthe locking shaft. The spines 56 correspond to a continuous portion ofthe locking shaft 36 and may be capable of transmitting axial forcesalong their length to the adjoining portions of the locking shaft. Asdiscussed previously, the spines may be defined by a plurality of cuts54 formed on opposing sides of the locking shaft within the flexibleportion 70. For example the cuts may extend partially around thecircumference of the locking shaft 36 and may be spaced apart axiallyalong the length of the flexible portion 70 with the spines locatedbetween the opposing sets of cuts. The spines 56 and the cuts 54 mayinteract to form a plurality of flexible segments 72 joined together bya plurality of living hinges 74. Adjacent flexible segments 72 may pivotrelative to one another about the intervening living hinges 74. Thisrelative pivoting of the flexible segments may impart the flexibility tothe locking shaft within the flexible portion 70. In addition, it is theorientation of the spines 56 and the cuts 54 that define thepreferential bending direction 58 about an axis of rotation of theliving hinges 74. Without wishing to be bound by theory, the livinghinges 74 exhibit increased bending resistance in directions other thanthose corresponding to pivoting of the living hinges 74 about the axesof rotation of the living hinges. Thus, directions in which the livinghinges 74 exhibit increased stiffness may be viewed as corresponding todirections of bending resistance (see FIG. 4). In the depictedembodiment, a direction of bending resistance 60 (FIG. 4) may correspondto a direction that is perpendicular to the preferential bendingdirection 58 and parallel to the axes of rotation of the living hinges74 of the locking shaft 36.

FIG. 17 depicts a schematic side view of the distal end of a firstarticulating shaft 32, which may be an inner articulating shaft whenarranged coaxially with a second articulating shaft 34 shown in FIG. 18.As discussed previously, the first articulating shaft includes a spine44 extending along the length of a flexible portion 80 of the firstarticulating shaft. Similar to the above, the spine 44 corresponds to acontinuous portion of the first articulating shaft 32 and may be capableof transmitting axial forces along its length to adjoining portions ofthe first articulating shaft, though unlike the locking shaft 36, thefirst articulating shaft has only a single spine 44. Moreover, the spinemay be defined by a plurality of cuts 40 formed around a portion of thecircumference of the first articulating shaft within the flexibleportion 80, and the cuts may be spaced apart axially along the length ofthe flexible portion 80. Similar to the above, the spine 44 and the cuts40 my interact to form a plurality of flexible segments 82 joinedtogether by a plurality of living hinges 84. Adjacent flexible segments82 may pivot relative to one another about the intervening living hinges84. Without wishing to be bound by theory, the living hinges 84 exhibitincreased bending resistance in directions other than thosecorresponding to pivoting of the living hinges 74 about the axes ofrotation of the living hinges. This relative pivoting of the flexiblesegments may impart the flexibility to the first articulating shaft 32within the flexible portion 80. Moreover, the orientation of the spine44 and the cuts 40 define a preferential bending direction 48 parallelto the axes of rotation of the living hinges 84 of the firstarticulating shaft 32.

In addition, the first articulating shaft 32 may include one or morefastener retention features such as tabs 76 at the distal end of thefirst articulating shaft. Without wishing to be bound by theory, suchtabs may aid in maintaining one or more fasteners at a desired positionbefore or during deployment of fasteners from the surgical instrument.

Similar to FIG. 17, FIG. 18 depicts a schematic side view of the distalend of the second articulating shaft 34, which may be an outerarticulating shaft when arranged coaxially with the first articulatingshaft 32. Similar to the above, the second articulating shaft includes aspine 46 along the length of a flexible portion 90 of the secondarticulating shaft, and the spine 44 corresponds to a continuous portionof the second articulating shaft 34 that may be capable of transmittingaxial forces along its length to adjoining portions of the secondarticulating shaft. The spine may be defined by a plurality of cuts 42formed around a portion of the circumference of the second articulatingshaft within the flexible portion 90, and the cuts may be spaced apartaxially along the length of the flexible portion 90. Similar to theabove, the spine 46 and the cuts 42 my interact to form a plurality offlexible segments 92 joined together by a plurality of living hinges 94.Adjacent flexible segments 92 may pivot relative to one another aboutthe intervening living hinges 94. This relative pivoting of the flexiblesegments may impart the flexibility to the second articulating shaft 34within the flexible portion 90. Moreover, the orientation of the spine46 and the cuts 42 define the preferential bending direction 50 parallelto the axes of rotation of the living hinges 94.

When the first articulating shaft 32 and second articulating shaft 34are assembled (e.g., coaxially arranged relative to one another asillustrated in FIGS. 4-5), the second articulating shaft may be rotated180 degrees relative to the arrangement shown in FIG. 18, such that thespine 46 of the second articulating shaft is located on a side of theelongated shaft assembly that is opposite the spine 44 of the firstarticulating shaft 32. The inventors have recognized that locating thespines on opposing sides of the elongated shaft assembly may result inan increased stiffness for the elongated shaft assembly. As notedpreviously, such an increased stiffness may be advantageous to avoidundesired deflection or movement of the elongated shaft assembly, forinstance, during actuation of the surgical instrument to deploy afastener into tissue.

As illustrated in FIGS. 17 and 18, the spines 44 and 46 of the first andsecond articulating shafts 32 and 34, respectively, may have a taperedconfiguration. For example, the spine 44 of the first articulating shaftmay have a first width d₁ at a distal end of the spine that is smallerthan a second width d₂ at a proximal end of the spine 44. In someembodiments, the first width d₁ may be between about 1.5 mm and about2.2 mm and the second width d₂ may be between about 3.5 mm and about 4.0mm. Similarly, the second spine 46 of the second articulating shaft mayhave a third width d₃ at a distal end of the spine that is smaller thana fourth width d₄ at a proximal end of the spine 46. In someembodiments, the third width d₃ may be between about 2.6 mm and about3.0 mm and the fourth width d₄ may be between about 4.3 mm and about 4.8mm. Depending on the particular embodiment, the various cuts of thefirst and second articulating shafts may extend circumferentiallybetween about 240 degrees and about 300 degrees the articulating shaftsto define the tapered spine configurations. However, it should be notedthat while specific ranges of dimensions are given herein for the cuts,spines, and other features, other ranges both larger and smaller thanthose disclosed herein may be used as the disclosure is not so limited.

Without wishing to be bound by theory, such a tapered configuration forthe spines may impart enhanced flexibility to the flexible portions 80and 90 at the distal ends thereof, while imparting progressivelyincreasing rigidity towards the proximal ends. In this manner, thetapered spines may provide the articulating shafts with enhanced overallrigidity while still being flexible enough to permit articulation of theelongated shaft assembly. Moreover, in some embodiments, the taperedspines may provide for a more uniform rigidity along the length of thespines compared to a configuration with constant width spines. Inparticular, the increased width of the tapered spines in the proximalportions thereof may correspond to locations along the elongated shaftassembly that experience a larger bending moment compared to locationsnear the distal tip (e.g., due to a larger moment arm at locationsfurther from the distal tip). Correspondingly, the increased rigidity ofthe tapered spines in these proximal locations may at least partiallyoffset the larger bending moments, thus providing a more uniform bendingrigidity along the length of the elongated shaft assembly.

Depending on the particular embodiment, the various cuts, spines, andflexible segments of the articulating shafts and/or locking shaft mayhave dimensions chosen to provide a desired rigidity and/or flexibilityfor the elongated shaft assembly. For example, the first and/or secondarticulating shafts may have diameters between about 3.5 mm and about5.5 mm and a wall thickness between about 0.13 mm and about 0.30 mm, andthe locking shaft may have a diameter between about 5.5 mm and 6.4 mmand a wall thickness between about 0.07 mm and about 0.15 mm. In oneexemplary embodiment, the first articulating shaft has a diameter ofabout 4.8 mm and a wall thickness of about 0.025 mm, the secondarticulating shaft has a diameter of about 5 mm and wall thickness ofabout 0.18 mm, and the locking shaft has a diameter of about 5.6 mm andwall thickness of about 0.13 mm. Although the first and secondarticulating shafts and the locking shaft have different wallthicknesses in this embodiment, it should be understood that the currentdisclosure is not so limited. For instance, in other embodiments, thefirst articulating shaft may have a smaller wall thickness than thesecond articulating shaft and/or locking shaft, or the articulatingshafts and locking shaft may have approximately the same wall thickness.

Moreover, in some embodiments, a spacing between adjacent cuts on thearticulating shafts and locking shaft may be between about 0.6 mm andabout 2.2 mm. In one exemplary embodiment, a spacing between adjacentcuts may be about 1 mm for the first and second articulating shafts, andabout 1.5 mm for the locking shaft. Additionally, each of the firstarticulating shaft, second articulating shaft, and locking shaft mayinclude cuts having different widths. For example, in one exemplaryembodiment, the first articulating shaft has cuts with a width of about0.007 mm to about 0.03 mm (e.g., about 0.02 mm), the second articulatingshaft has cuts with a width of about 0.07 mm to about 0.18 mm (e.g.,about 0.09 mm), and the locking shaft has cuts with a width of about0.10 mm to about 0.18 mm (e.g., about 0.14 mm). In some embodiments, thewidth of the cuts on the locking shaft may be selected such thatopposing sides of the cuts do not come into contact when the elongatedshaft assembly is in a fully articulated configuration. For example, theinventors have found that such configurations may aid in permittingmovement of the driveshaft (e.g., during deployment of a fastener) whenthe elongated shaft assembly is articulated. However, it should beunderstood that other dimensions for the spacing and width of the cuts,including ranges both smaller and larger than those noted above, may besuitable in some embodiments to provide a desired rigidity and/orflexibility of the elongated shaft assembly.

Depending on the embodiment, cuts formed in articulating and/or lockingshafts may extend along a length of a flexible portion of eachrespective shaft in the articulable portion of the elongated shaftassembly. For example, in some embodiments, the length of the flexibleportions of each shaft may be about 26 mm to about 42 mm. In someembodiments, the first and second articulating shafts may have flexibleportions having the same length or different lengths. For example, thefirst articulating shaft may have a flexible portion with a length ofabout 26 mm to about 42 mm, and the second articulating shaft may have aflexible portion with a length of about 26 mm to about 38 mm. In certainembodiments, the lengths of the flexible portions of the first andsecond articulating shafts may be selected such that length of theflexible portion of the first shaft is equal to or longer than thelength of the flexible portion of the second shaft.

In addition to the above, in some embodiments, and as shown in FIGS.16-18, cuts formed in the various shafts may terminate in stress reliefscollocated with the living hinges. The stress reliefs may be shaped toaid in avoiding fatigue and/or failure of the living hinges uponrepeated bending of the flexible portions, for example, when theelongated shaft assembly is moved back and forth between thenon-articulated and articulated positions. In some embodiments, thestress reliefs may have an elliptical shape, though other shapes such ascircles also may be suitable.

In addition to the above, while several patterns of cuts and spines aredisclosed regarding the flexible portions of the locking shaft andarticulating shafts, it should be understood that other patterns of cutsand spines are also possible. For example, the flexible portions of theshafts corresponding to the articulable portion of the elongated shaftassembly may be constructed and arranged in any appropriate fashion suchthat the flexible portion preferentially bends in at least onedirection. Additionally, while spines with linear tapers have beendepicted, embodiments in which the spines follow a non-linear taper arealso contemplated.

FIGS. 19-20 depict one embodiment of a driveshaft 30 that may beemployed in a surgical instrument to impart a distally directed force todeploy a fastener from the surgical instrument, for instance, viareciprocal axial displacement of the driveshaft. As shown in FIG. 3, thedriveshaft may be coaxially arranged within the articulating shafts andthe locking shaft, though other arrangements also may be suitable. Inthe depicted embodiment, the drive shaft includes a flat side 302 whichmay be constructed and arranged to engage a corresponding flat surfaceon the heads of the fasteners, as discussed in more detail below. Theengagement of the flat surfaces may maintain the fasteners in a desiredorientation within the driveshaft, including when the elongated shaftassembly is articulated. Moreover, the driveshaft may include a flexibleportion 310 in which a pair of spines 304 are defined by a two pluralityof cuts 306 extending partially around a circumference of the driveshaftand located on opposing sides of the driveshaft. The cuts are spacedalong a length of the flexible portion similar to the locking shaftdescribed above. Similar to the locking shaft, the spines 304 and thecuts 306 my interact to form a plurality of flexible segments 308 joinedtogether by a plurality of living hinges 312, and adjacent flexiblesegments 308 may be pivoted relative to one another about theintervening living hinges 312.

As illustrated in FIGS. 19-20, the cuts may be arranged at anon-orthogonal angle relative to a longitudinal axis of the drive shaft.In some embodiments, the cuts may be arranged such that they follow ahelical path around the driveshaft. Without wishing to be bound bytheory, this arrangement may place the cuts of the driveshaft 30 at anangle relative to the cuts located on the articulating shafts 32 and 34which may aid in avoiding binding of the cuts on the driveshaft with thecuts on the articulating shafts. For example, any single angled cut 306of the driveshaft would only contact an adjacent cut on the firstlocking shaft 32 at only a single point, thereby reducing thepossibility of the cuts binding on one another as the driveshaft isdisplaced relative to the articulating shafts during deployment of afastener.

Depending on the particular embodiment, the cuts on the driveshaft mayhave a width between about 0.07 mm and about 0.13 mm, and a spacingbetween adjacent cuts may be between about 0.8 mm and about 1.4 mm. Insome embodiments, the cuts may define spines along the length of thedriveshaft, and the spines may have a width ranging from about 0.5 mm toabout 1.3 mm. Moreover, the cuts may extend along a flexible portion ofthe driveshaft, and the flexible portion may have a length of about 38mm to about 54 mm. In certain embodiments, the length of the flexibleportion of the driveshaft may be equal to or longer than a length of aflexible portion of an outer articulating shaft plus a travel distanceof the driveshaft. Such a configuration may aid in permitting sliding ofthe driveshaft (e.g., during deployment of a fastener) while theelongated shaft assembly is in an articulated configuration.

In addition to the above, a driveshaft 30 may include fastener engagingfeatures such as tabs 314 at a distal end of the driveshaft that extendin a distal direction and are oriented radially inwards. Therefore, whenthe trigger of the surgical fastener is actuated, the tabs may engagewith a distal-most fastener to apply a distally directed force to thefastener to deploy the fastener from the distal end of the elongatedshaft assembly. However, other configurations for applying a force to adistal most fastener are also envisioned as the disclosure is not solimited.

Referring now to FIGS. 21-23, one embodiment of a fastener levelindicator system 28 is described in more detail. As discussedpreviously, the fastener level indicator system may be constructed andarranged to provide an indication of the number of fasteners availablefor deployment from the surgical instrument. For example, FIG. 21depicts a rear perspective view of a surgical instrument including awindow 502 through which an indicator may be viewed. As shown in FIG.22, the fastener level indicator system 28 may include an indicator 504in the form of a gear cylinder. For instance, an upper surface of theindicator may be viewable through window 502. The indicator is coupledto a reciprocating arm 506, which may be coupled to the trigger 12 ofthe surgical instrument in any suitable manner such that upon actuationof the trigger (and deployment of a fastener), the reciprocating arm ismoved to rotate the indicator to a new position. For example, the newposition may indicate that one fewer fastener remains for deploymentfrom the surgical instrument.

As illustrated in FIGS. 22-23, the reciprocating arm may be coupled tothe indicator via an actuator 508 that is positioned within the gearcylinder of the indicator 504. As depicted in FIG. 23, which shows aperspective bottom view of the fastener level indicator system 28, theactuator 508 includes a resilient arm 508 with a tooth 512 at the end ofthe arm. The tooth 512 is constructed and arranged to engagecorresponding gear teeth 514 located on the interior of the indicatorgear cylinder 504. In this manner, the resilient arm and teeth 512 and514 form a clutch-type interface between the actuator 508 and theindicator 504, such that rotation of the actuator in a first directioncauses associated rotation of the indicator (e.g., to move the indicatorto a new position), while rotation of the actuator in the oppositedirection causes the resilient arm 510 to deflect inwardly such that theindicator is not rotated. Accordingly reciprocal movement of thereciprocal arm 506, which may cause associated rotation of the actuatorin the first and second directions, does not cause the indicator to movebackwards. Moreover, in some embodiments, the fastener level indicatorsystem includes a stationary arm 516 that includes a tooth 518constructed and arranged to engage corresponding teeth 520 formed on theoutside of the indicator gear cylinder. The engagement of the teeth 516and 520 may be arranged to block backwards rotation of the indicator.

While the present teachings have been described in conjunction withvarious embodiments and examples, it is not intended that the presentteachings be limited to such embodiments or examples. On the contrary,the present teachings encompass various alternatives, modifications, andequivalents, as will be appreciated by those of skill in the art.Accordingly, the foregoing description and drawings are by way ofexample only.

What is claimed is:
 1. A surgical instrument comprising: a handle; andan elongated shaft assembly extending distally from the handle, theelongated shaft assembly including an articulable portion movablebetween a non-articulated configuration and an articulatedconfiguration, the elongated shaft assembly comprising: a firstarticulating shaft; and a second articulating shaft coaxially arrangedrelative to the first articulating shaft and axially fixed relative tothe first articulating shaft at a location located distally from thearticulable portion of the elongated shaft assembly, wherein a proximalportion of the first articulating shaft is displaceable in a distaldirection and a proximal portion of the second articulating shaft isdisplaceable in a proximal direction to move the articulable portion ofthe elongated shaft assembly from the non-articulated configuration tothe articulated configuration.
 2. The surgical instrument of claim 1,wherein the proximal portion of the first articulation shaft isdisplaceable in the proximal direction and the second articulating shaftis displaceable in the distal direction to move the articulable portionof the elongated shaft assembly from the articulated configuration tothe non-articulated configuration.
 3. The surgical instrument of claim1, wherein displacing the proximal portion of the first shaft in thedistal direction applies a compressive stress to first articulatingshaft, and wherein displacing the proximal portion of the second shaftin the proximal direction applies a tensile stress to the secondarticulating shaft.
 4. The surgical instrument of claim 1, furthercomprising an articulation control that controls displacement of theproximal portions of the first and second articulating shafts.
 5. Thesurgical instrument of claim 4, further comprising: a first shuttlecoupled to the articulation control and the proximal portion of thefirst articulating shaft; and a second shuttle coupled to thearticulation control and the proximal portion of the second articulatingshaft, wherein the first and second shuttles are axially moveablerelative to the elongated shaft assembly.
 6. The surgical instrument ofclaim 5, further comprising a locking shaft that selectively preventsarticulation of the articulable portion of the elongated shaft assemblywhen the locking shaft is in a first locked configuration and permitsarticulation of the articulable portion of the elongated shaft assemblywhen the locking shaft is in a second unlocked configuration, andwherein movement of the articulation control from a first position to asecond position moves the locking shaft from the first lockedconfiguration to the second unlocked configuration.
 7. The surgicalinstrument of claim 6, wherein moving the articulation control from thesecond position to a third position displaces the first shuttle in thedistal direction and the second shuttle in the proximal direction.
 8. Amethod of operating a surgical instrument, the method comprising:displacing a proximal portion of a first articulating shaft of anelongated shaft assembly of a surgical instrument in a proximaldirection, the elongated shaft assembly including an articulable portionmovable between a non-articulated configuration and an articulatedconfiguration; displacing a proximal portion of a second articulatingshaft of the elongated shaft assembly in a distal direction, the secondarticulating shaft coaxially arranged relative to the first articulatingshaft and axially fixed relative to the first articulating shaft atlocation located distally from an articulable portion of the elongatedshaft assembly; and articulating the elongated shaft assembly from thenon-articulated configuration to the articulated configuration, at leastin part, due to the displacement of the proximal portion of the firstarticulating shaft and the proximal portion of the second articulatingshaft.
 9. The method of claim 8, further comprising: displacing theproximal portion of the first articulating shaft in the distaldirection; displacing the proximal portion of the second articulatingshaft in the proximal direction; and moving the elongated shaft assemblyfrom the articulated configuration to the non-articulated configuration,at least in part, due to the distally directed displacement of theproximal portion of the first articulating shaft and the proximallydirected displacement of the proximal portion of the second articulatingshaft.
 10. The method of claim 8, further comprising applying acompressive stress to the first articulating shaft and applying atensile stress to the second articulating shaft.
 11. The method of claim8, further comprising moving an articulation control of the surgicalinstrument to control displacement of the proximal portions of the firstand second articulating shafts.
 12. The method of claim 11, furthercomprising: displacing a first shuttle in the distal direction, whereinthe first shuttle is coupled to the articulation control and theproximal portion of the first articulating shaft; and displacing asecond shuttle in the distal direction, wherein the second shuttle iscoupled to the articulation control and the proximal portion of thesecond articulating shaft in the proximal direction, and wherein thefirst and second shuttles are axially movable relative to the elongatedshaft assembly.
 13. The method of claim 12, further comprising: movingthe articulation control from a first position to a second position tomove a locking shaft of the surgical instrument from a first lockedconfiguration to a second unlocked configuration, wherein the lockingshaft selectively prevents articulation of the articulable portion ofthe elongated shaft assembly when the locking shaft is in the firstlocked configuration and permits articulation of the articulable portionof the elongated shaft assembly when the locking shaft is in the secondunlocked configuration.
 14. The method of claim 13, further comprisingmoving the articulation control from the second position to a thirdposition to displace the first shuttle in the distal direction and thesecond shuttle in the proximal direction.
 15. A surgical instrumentcomprising: a handle; and an elongated shaft assembly extending distallyfrom the handle, the elongated shaft assembly including an articulableportion movable between a non-articulated configuration and anarticulated configuration, the elongated shaft assembly comprising: afirst shaft including an articulable portion having a first plurality ofcuts spaced along a first length of at least a distal portion of thefirst shaft, wherein each cut of the first plurality of cuts extendspartially around a circumference of the first shaft to define a firstspine extending along the first length of the first shaft, the firstspine having a first width at a distal end of the first spine and asecond width greater than the first width at a proximal end of the firstspine; and a second shaft coaxially arranged relative to the firstshaft, the second shaft including an articulable portion having a secondplurality of cuts spaced along a second length of at least a distalportion of the second shaft, wherein each cut of the second plurality ofcuts extends partially around a circumference of the second shaft todefine a second spine extending along the second length of the secondshaft, the second spine having a third width at a distal end of thesecond spine and a fourth width greater than the third width at aproximal end of the fourth spine, wherein the first spine is located ona first side of the elongated shaft assembly, and the second spine islocated on a second, opposing side of the elongated shaft assembly. 16.The surgical instrument of claim 15, wherein the first and second spinesare parallel to a longitudinal axis of the elongated shaft assembly. 17.The surgical instrument of claim 15, wherein the first and second spinesare curved along a length of the first and second shafts.
 18. Thesurgical instrument of claim 15, wherein a width of each cut of thesecond plurality of cuts is selected such that opposing edges of eachcut of the second plurality of cuts come into contact when the elongatedshaft assembly is in the articulated configuration.
 19. The surgicalinstrument of claim 15, further comprising a driveshaft disposed withinthe first and second shafts, the driveshaft including a third pluralityof cuts spaced along at least a portion of a length of the driveshaft,wherein each cut of the third plurality of cuts forms at most onecontact point with a cut of the first or second pluralities of cuts. 20.The surgical instrument of claim 19, wherein a width of each cut of thethird plurality of cuts is selected such that opposing edges of each cutof the third plurality of cuts do not come into contact when theelongated shaft assembly is in the articulated configuration.
 21. Thesurgical instrument of claim 15, wherein the each cut of the first andsecond plurality of cuts has a width of between about 0.007 mm and about0.018 mm.
 22. The surgical instrument of claim 15, wherein a spacingbetween the each cut of the first and second plurality of cuts betweenabout 0.6 mm and about 1.4 mm.
 23. The surgical instrument of claim 15,wherein the first width is between 1.5 mm and about 2.2 mm and thesecond width is between about 3.5 mm and about 4.0 mm.
 24. The surgicalinstrument of claim 15, wherein the third width is between about 2.6 mmand about 3.0 mm and the fourth width is between about 4.3 mm and about4.8 mm.